So the President of the United States

believes his relationship with other world leaders is a "10"?
I rather think that no world leader has ever had that sort of relationship with other world leaders. 
They may seem to get along well together and they may work together to get things done but do they choose to go on holiday together? Yes, people get invited to Camp David or Chequers or Admiralty House or whatever the German, Russian, Chinese and so on equivalents are but that is all part of the political game.
The Senior Cat and I had one of those lunch time discussions yesterday. He is currently reading an Ian Rankin novel he somehow missed out on. (The Senior Cat is an avid Rankin fan.) 
    "Do you think there really is tension in the police force?" he asked me.
My answer to that was,"Absolutely."
"Why?" he wanted to know.
I thought about it. It is something I have often observed here. It has something to do with the training they receive. I once had a conversation with a police officer on the train. He had helped me put the trike on the train and started to talk to me. From his accent it was obvious that  he had not been born here. I asked him,
     "Did you train in the UK?"
     "Yes. Shows does it?" 
I admitted that it did and he admitted that he was going back to the UK because he wasn't happy with the way he was expected to relate to the public here. We agreed that "friendly" was not a  word you would readily use in relation to our police force. Somehow we haven't managed to reach a balance between "care" and "control".
I vividly remember the young policewoman charged with the task of telling the Senior Cat his cousin had died. Yes, she did it kindly enough but of course there was a natural reservation there. She didn't want to get involved. It was not her job to get involved. Her partner did not even sit down when invited to do so. I suspect he had actually been trained not to do that. 
My limited relationship with the London police force suggested that yes, there is tension there between the senior and junior officers. It is about maintaining control, about ensuring that your subordinates obey commands without question in an emergency.  I once had to give a police officer my resident's key to one of the locked London square gardens. It was a young constable who asked me if I had one. When I offered it to him he asked me to give it to the sergeant, the person who would take responsibility for returning it. 
I suspect Rankin - and others - are correct when they write tension into the relationships. It isn't just about good story telling but about what actually happens in real life. It's about maintaining control.
Are world leaders like that too? Have they just borrowed the key so they can get into the garden for a time? Eventually they need to leave and give the key back. Inviting others to join them in the garden means taking responsibility for them doing no damage. It's a risky business.